1. Field of the Invention
This invention relates to a control apparatus for an air-conditioner for performing air-conditioning in a room taking into consideration the perceived temperature of persons in the room.
2. Description of the Related Art
A conventional control apparatus for an air-conditioner usually controls the blower motor, the damper for switching between inside and outside air, the air mixing damper, etc. to determine the required blowing temperature of the room air temperature in accordance with the actual room temperature and the temperature setting to maintain the actual room temperature at the temperature setting.
Such a system attempts to constantly realize comfortable air-conditioning in a room or in a car by correcting the set blowing temperature, taking into consideration the outside temperature and the amount of heat from the sun. With a conventional apparatus, the determination of the required blowing temperature or the determination of the target room temperature and other air-conditioning control, is based only on environmental conditions such as the outside temperature and heat from the sun. Therefore, it is difficult to say that the comfort requirements of passengers are precisely reflected. This is due to the fact that with a conventional apparatus, the comfort conditions of passengers in a car are not clearly detected.
In a conventional apparatus, apart from the idea of controlling only the temperature of the blown air, it is usual to use a system which sets the amount of air blown in accordance with the deviation between the room temperature and the temperature setting. The amount of air blown may also be based on the deviation between the room temperature and the temperature setting, to supply a large amount of air when the deviation is large and a small amount when small.
Even with such a system, however, it is difficult to say that the control of air blown can supply a comfortable amount of air. The temperature sensation, which is an important factor of comfort, is influenced not only by temperature but also by the air flow, humidity and heat from the sun as well as human factors; such as the amount of movement and clothes.
In order to deal with the defects of the prior art, the inventors considered to perform room air-conditioning by paying attention to the following facts:
(1) There is a strong relationship between the skin temperature of persons in a room and their perceived temperature sensations (hot and cold feeling).
(2) Under abnormal conditions, the room air-conditioning most comfortable for persons in a room is one where they feel cool when their skin temperature is high and where they feel hot when their skin temperature is low.
It has been confirmed through experiments that in order to realize conditions of non-sensation of temperature mentioned above, the factors of persons in the room such as the amount of their movement (amount of metabolism) and amount of clothes worn should be taken into consideration in addition to environmental conditions such as temperature, humidity, air flow, and heat from the sun. As a result of experiments, it has been found that the skin temperature of persons in a room corresponds to the conditions of non-sensation mentioned above and determined by all factors, including the environmental factors and the factors of the person in the room as stated above. This means that if air-conditioning is controlled based on skin temperature, it is not necessary to take into consideration the effects of room size and thermal load, which are problems with conventional air-conditioning technologies.
As mentioned above, it is possible to determine the temperature sensation of the persons in the room under normal conditions from their skin temperature. It is necessary, however, to take into consideration not only the skin temperature but also the rate of change of skin temperature over time under non-stable conditions of room temperature from immediately after persons enter the room until their skin temperature stabilizes. This may be expressed by the following equation EQU S=K.sub.1 .times.T.sub.S +K.sub.2 .times.T.sub.S +C (1)
where,
K.sub.1, K.sub.2, C: Constants PA1 T.sub.S : Skin temperature PA1 T.sub.S : Rate of skin temperature change
As shown above, the temperature sensation changes along with the skin temperature.
In order to make air-conditioning comfortable, it is necessary, to control the room air conditioning taking into consideration the skin temperature (perceived temperature) of persons in the room.
Moreover, if a control apparatus for an air-conditioner controls the amount of air blown as in the conventional apparatus, persons in the room may feel uncomfortable while: the skin temperature is in the process of reaching a comfortable temperature; or after it reaches a comfortable temperature and the relationship between the temperature, sensation and skin temperature and the relationship with the amount of air blown are not taken into consideration at all.
Also, in conventional apparatus there was a problem of persons feeling uncomforatable due to the noise of air being blown and the air flow even if satisfied with the temperature sensation, especially when the amount of air blown was excessive.
Therefore, it is necessary to supply the amount of air in response to the temperature sensation, which changes along with the skin temperature.